Telephone switch device



(No Model.)

C. E. BUELL.

TELEPHONE SWITCH DEVICE.

Patented Deo. 20,1881.

INETD CimEzzel 7* wr, wmungun. DA c.

WI'I NESSES' UNITED STATES PATENT EEicE.

CHARLES E. BUELL, OF NEW HAVEN, CONNECTICUT, ASSIGNOR OF TVO- THIRDS TOJAMESv G. SMITH,

OF HACKENSACK, NEV JERSEY, AND

GEORGE W. CCY, OF MILFORD, CONNECTICUT.

TELEPHONE SWITCH DEVIC.

SPECIFICATION forming part of Letters Patent No. 251,178, dated December20, 1881,

Application filed September 24, 1881. (No model.)

T 1 all whom it may concern Be it known that I, CHARLES E. BUELL, acitizen of the United States, residing at New Haven, in the county ofNew Haven and State 5 of Connecticut, have invented certain new anduseful Improvements iu Telephone Switch De- \'ices,of which thefollowing is a specification.

In an application for patent filed by me March 22, 1881, N o. 29,4538,of which this presentapplication is a division, I have described aninvention the object of which is to simplify the construction andarrangement of apparatus at subscribers stations of telephone-lines andto do away with the use of local batteries.

In carrying out that invention I have proposed to arrange ateachsubscribers station van induction-coil whose primary coil may beconnected to the line-circuit, to connect the receiving-telephone ateach station in a local circuit ith the secondary of said induction`coil, and for purposes of oral communication to place the contacttransmitters directly in the line-circuit, which is itself to be chargedduring oral communication,between two points by a battery or generatorat the central office, or at either or both of' said points. proposed toplace at each station of a line arranged as above described a switchdevice electrically controlled from the central office, and providedwith a spring or equivalent locking device controlled by the weight of'the telephone, the whole so arranged that when the line is not in use atanystation the removal of the telephone will automatically lock thetransmitter and the primary ot' the ind uction-coil in circuit, whileit' the telephone is removed from its hook when the line is in use atother sta-- tions and properly charged by a battery at the centraloffice the switch will be locked in position so that the circuit throughthe transmitter and induction-coil will be held broken, and the branchcircuit completed by the movement of the switch when charged by thebattery at the central office will be held closed.

My present application relates to the switch device last referred to,and also to the centraloffice switch apparatus employed in connectiontherewith and with telephone-lines whose subscribers7 stations areprovided with induction- 5o coils and telephone-instruments connected toI have also line and to one another according to the invention whichforms applica-tion.

Figure l is a diagram illustrating one plan ot' arranging telephoneapparatus according 55 to the invention which forms the subject ot' myapplication before referred to. Fig. 2 shows the manner of applying theautomatic switch which forms the subject of the present application, andshows also the central-office 6o apparatus to be used with said switchor with a telephone system in which the subscribers station apparatus isconstructed iu the manner indicated in Fig. l.

In Fig. 1 the apparatus at each thus arranged:

A is a gravity-switch connected to line on that side ot' the stationnearest the central ot'- ice, and making contact, when depressed by theweight ofthe magneto-telephone t, with a 7o contact-stop, 1, joinedthrough a circuit-breaking or signaling key, k, and a signal-bell, S,with the line on the other side of the station. The magneto-telephone tis connected in local circuit with the secondary of an inductioncoil, I.

M indicates a battery or contact transmitter of any approvedconstructioli,whose electrodes are directly in a circuit passing fromthe contact-stop 2 of the switch through the primary 8o of theinduction-coil to the point a, where connect ion is made with the line.When the switch is relieved from the weight of the telephone, contact ismade with the point 2, and the mainline circuit is then directly throughthe battery-transmitter and the primary of the induction-coil, while atthe same time the circuit through the signal-bell S and the key K isbroken.

C designates a central station, and D a 9o charging-battery locatedthereat, which is connected to line when oral communication takes placebetween any two of' the stations represented.

Bell S and key K are for use in the ordinary manner in conjunction withthe usual apparatus employed at the central station.

For the purposes of oral communication b'etween any two stations theswitches at those stations are so manipulatedk as to place the Icotransmitter M and primary of induction-coil I direct-1y in the mainline, and the battery D at the subject of my prior station is 65 thecentral ofce is connected to the line. Under these circumstances it isobvious that either transmitter, when spoken to, will vary in thewell-known manner the current of battery D passing through the primariesot'I, and the result will be a succession ot'secondary pulsations iu thetelephonesT in a manner to produce articulate sounds.

I do not design limiting` myself to any particulararrangementorconstruction oi switches and devices, as there are many well known inthe art, and I contempla-te the employment ot' others besides those heredescribed. It is evident that the charging-battery may be placed ateither of the points that are telephonically connected.

In Fig. 2 I have shown a modified arrangement of devices at thesubscribers station forming the subject of this application. In thisplan I employ a provision for cuttingr the transmitter and primary ofthe induction-coil out of the circuit when the line is in use at anotherstation, or stations. I have also means whereby, when the line is not inuse and the receiving-telephone at any station is removed from itssupport, the transmitter and telephone at that station are locked incircuit and the operation of an electro-magnetic switch controlled bythe central ot'lice can be only made effectual to cut out thetransmitter and induction-coil of other stations. For this purpose Imake use at the subscribers station of an electro-inagnetic switchadjusted above a normal weak current and provided with contacts andccnneetions so arranged that when against its back stop the main-linecircuit will be through the transmitter and induction-coil, but whenoperated by a current of suiicient strength it will break said firstcircuit and complete a branch circuit around the transmitter andinduction-coil. For the purpose of signaling to the central stationwithout affecting said.

switch, I may decrease still further the tension ofthe normalline-current, or may entirely break it.

G designates a case, to the cover of which is secured a contact orbattery transmitter, whose diaphragm isindicated at H and electrodesatE.

I? is an arm supporting the movable or adjustable electrode. Theautomatic switch is controlled by the electro-magnet of the callbell,and consists of the armature lever and bell-hammer, connected directlythrough electromagnet E M with the line-wire on the side leading to thecentral station, and provided with contact-stops 5 and 6, one connectedto the line-wire on the other side of the station and the other with theprimary of the induction-coil I, the hinges ot' the box, thecircuitbreaking call-key k, (shown in bottom view,) the diaphragm of thetransmitter and electrode in contact therewith, and to the line-wire L.The secondary of the induction-coil I is connected to thereceiving-telephone T,bypref erence permanently.

The telephone-support R consists of a bladespring, or ofany suitablespring-actuated support. It is provided with a locking-point, 7, ofsuitable shape, which engages with the switch lever, when it is relievedfrom the weight ot' the telephone, upon the one side or the otherthereof, according as said switch-lever is drawn forward by theelectro-magnet or is against its back stop, and, according to thecondition ofthe switch, locks the transmitter and induction-coil into orout of circuit. With a normal or weak current to line, which is designedto be broken or weakened by signaling-key K, and tothereby affectdelicatelyadjusted apparatus at the central station, the switch-lever isin the position shown in full lines, the strength ofcurrent beinginsufficient to draw it forward against the stress ot' itsretractilespring T, as adjusted. The path ot the main-line current at this andother stations upon the same line is then through electro magnet E M,switch-lever 3, back stop, 5, induction-coil I, key K, and transmittercontacts. By stillfurther weakening the normal current, or by breakingthe circuit by key K, or in any other suitable manner, a call may besent to the central office. The removal of the telephone T from itssupport will allow the same to rise, and the locking-point upon the endthereof will come into position to lock the lever in the condition shownin full lines, with the circuit through the transmitter. For the purposeof cutting out the transmitter and induction-coil at other stations, anincreased battery is used during oral communication, which draws theswitch-lever forward and holds it in that position while the line is inuse. At all stations where the telephone is still attached to itssupport the lever will be free to move to break the circuit through thetransmitter and the induction-coil, and it will be held in the positionshown in dotted lines so long as the stronger or increased battery is toline. Under these circumstances the locking-point 7, when a telephone atany of such stations is removed from the support, willcome into positionto lock the armature against stop 6, in which position the circuitthrough 5 is broken.

The subscribers station may be called in the well-known manner byplacing to line a current of suiicient strength to overcome the stressof retractile spring T. Other specific devices may be used in place ol"those herein described, as the principle of the invention consists incausing the support for the telephone, when relieved of its presence, tolock an electro-magnetic switch controlled from the central office inposition to hold the circuit through the transmitter or the receivingdevices closed, so that when the switches are operated to hold thetransmitters or the receivers at other stations out ot' circuit theswitch at the station whose telephone is in use cannot be aiected.

Other arrangements ot' circuits and devices willreadily suggestthemselves to those skilled IOO IIO

IIS

-in the art, whereby the combined switch and -ized for this purpose.

It is obvious that such an arrangement of switch and lock might beadopted with the systems in ordinary use in which the line is chargednormally; but the battery is withdrawn from the line-circuit when thetelephones are in use. In such a case,however, the switch would bearranged to complete the circuits controlling the operation otl thecommunicating apparatus when drawn forward bythe electromagnet, and tobreak such circuits or close a shunt thereto when against its back stop.In otherrespectsits operation,iu conjunction with the lock-support forthe telephone, would be the same.

A central-ndice switch and one plan ot devvices for completing thenecessary connections through the charging-battery usedduring oralcommunication between subscribers on the same ordift`erentlines,orbetween a subscriber and the central ofce, is shown at C O. .For thesake of simplicity but four lines are shown, each of which is connectedto a vertical or line strip, S, in turn connected, when the lineisnot inuse, through switch-levers h, with a battery, M B. This battery is ofsufficient strength to chargethe electro-magnets of the annunciators andbells at the central office, but is not sui-ticient to operate theswitch and bell electromagnets at the subscribers stations.

The charging-battery to be used dui ing oral communication is shown at DB, one pole joined to a connecting strip or wire, n, and the other to asimilar connecting-strip, m, throughacircuit-breakingkey,K,andaswitch,12, which serves to make the connection directly through 13 orindirectly throughthe primary ot induction-coil I, electrodes oftransmitter M, and poiut14. The secondary of the` induction-coil isconnected7 asin the other iigures, to the receivingtelephone T. Theconnectingstrips or wires are provide-d with switches 17 and 19, whichmay be thrown into contact with the line-strips. The terminal switches1S may be placed in contact with a plate or strip, 20, connected toground.

K K designate calling-keys, which may control a separate battery, K B,for the purpose ot' signaling to a subscribers station after the mannerdescribedin patent to Geo. W. Coy, tiled February 17,1880, No. 224,653.I propose, however, to use for this in ordinary cases thecharging-battery D B. The annuneiators 1234 arearranged and adjusted togive a signal upon a weakening or breaking ot' the line-current frombattery M B. When the noninterference switches are used it is necessarythat the charging-battery DB used during oral communication should bestronger than the normal line-battery M B, for the purposes beforeexplained. W'hen, however, the arrangement shown in Figl is employed therelative strength of said batteries is immaterial, and the main orsignaling batteries or sections 'thereof may be under somecircumstances'the charging-battery. The strip 20 should, by pret'-erence, be normally connected to one ot'the connecting-strips-say ll-bya terminal switchlever, 18. Upon the reception ota signal from any lineits vertical strip is connected with battery D B by a switch lever, i8or 19, a-nd its switeh-leverh is disconnected. The charging-battery D Bis thus thrown to line, the circuit being from ground to bar 20, lever18, connecting-strip m, switch-point 1 2, transmitter M, induction-coilI, key-batteryvl) B, strip n, switch-lever 18 or 19, andl line-strip, toline. Conversation may then bel carried on between the subscriber andtheI central station through their battery-transmitters, which are iuthe direct circuit ofthe charging -battery and the primaries oftheinduction coils whose secondaries include the receiving-telephone.It'the lock-switches are used at the subscribers station, the result ofconnecting the battery D B to that particular line has been to cut outthe transmitting and receiving apparatus at all stations upon said lineexcepting at the station calling. Should the call be for a station uponthcsame line, the signal appropriate to that station maybe given bymanipulatingthe circuitbreaking key.v The charging battery is then to bewithdrawn from line for an instant to allow the subscriber called tolock his telephone in circuit, and alter that has been done the batteryis to be again placed to line, thus cutting out the apparatus atallother stations and placing the line in condition for oral communication.It' desired, the weaker battery M B may be placed to line when thestronger batteryis disconnected. andthe subscriber called may then givenotice of the t'act that he has removed his rcceivingtelephone from itssupport, so as to lock the switch, by operating his calling-key. Whenthis signal is received at the central office the battery D B is againintroduced and the connection to battery M B broken. It' the subscriberwith whom communication is desired is upon another line, the connectionofthe plate 2l) withstrip m is to be broken,and the lines may then beconnected through the linestrips and the charging-battery by throwingthe proper lineswitches 17 and 18 or 19. In the diagram lines l and 4are shown thus connected. Thepath ot the current may be readily traced.When the arrangement ot' switches shown in Fig. 1 is used the operationof the central-office switch is substantially the same asalreadydescribed. Under such circumstances, however, subscribers may becalled in the ordinary manner by circuit-breaking keys introduced in theseveral lines at the central office.

It is obvious that other switch mechanism may be used for the purpose ofmaking the desired connections and for introducing the charging-battery,and in practice the manipulation would be much simplified.

The central-ottice switch is shown in the form indicated to avoidconfusion.

IOC)

IIO

IIS

As many pairs of connecting-strips m aand as many charging-batteries D Bare to be used as may be required by the size ot' the exchange and thefrequency ot' the connections.

Instead ot' the switches 71, and 19 for each line, a single switch maybe used, its pivot connected to the line-strips, and its free endarranged to make connection with either of two studs, one connected tobattery M B and the other to strip u.

It' desired, an independent electro-magnet may be used instead ot' thebell electro-magnet for controlling the station-switch.

Instead of using a neutral electro-m agnet for the switch, I may employa polarized electromagnet, and control the same by changing the polaritywhen the line is charged for oral communication.

I do not in this application make any claim to the arrangement of theprimary coil and charging-battery in the main-line circuit and'thesecondary coil and receiver in the local circuit; nor do I malte anyclaim to the plan of arranging the primary1 in one loop or branch andthe bell in the other loop or branch, as shown in Fig. l, as these formthe subject of my prior application.

l/Vhat I claim as my invention is l. In a telephone-station apparatus, acontact-transmitter normally in the main-line circuit, in combinationwith an electro-magnetic switch whose back contact is included in thecircuit of said transmitter and whose front Acontact completes a branchcircuit around the same, substantially as described.

2. rIhe combination ot' an electro-magnetic switch in the main-linecircuit, connections through the transmitting or receiving apparatuscontrolled thereby, and a locking device released by the telephone forthe purpose of locking said switch in position where the circuit throughthe telephone apparatus will be closed.

3. In combination with an electro-magnetic switch-levercontrolling thecircuit-connections through a telephone, a spring telephone-supportarranged, when freed from the weight of the telephone, tolock theswitch-lever upon one side or other thereof, according as said lever isagainst its front or its back stop.

et. An electro-'magnetic switch controlling the circuits through theinstruments at a telephone-station, and located in the direct circuit atsaid station, in combination with mechanical locking devices broughtinto connection with said switch in the act of using the instruments,substantially as and tor the purpose described.

5. In a telephone-exchange system, two or morelines normallyconnectingtoearththrough a battery, and devices for connecting any twolines together through a battery of increased power, substantially asand for the purpose described.

6. In a telephone-exchange switch,one or more pairs of line-connectingstrips, each of which is connected to one pole of agenerator, and eachprovidedY with switch devices for connecting one ot' said strips toearth, substantially as and for the purpose described.

7. In a telephone-exchange switch, line-connecting strips andcircuit-connections tht ret'rom passing through a galvanic battery andcontact-points of a battery-transmitter, as and 'or 4the purposedescribed.

8. At each of a series of stations on a telephone-line, electro-magneticswitches whose y retractile devices are adjusted above the strength ofcurrent normally connected to said line, and which control throughsuitable connections the circuits ot telephone-instrnments, incombination with devices at a central station for increasing thestrength ot' current for the purpose of operating said switches.

9. An electro-magnetic switch at a station of a telephone-line, providedwith contacts and connections whereby the telephone may be thrown intoand out of operative electrical condition byincreasnganddecreasingthestrength of current upon the line, substantially asdescribed, in combination with a bell and a bellhammer attached to thevibrating portion ot' the switch.

l0. The combination of two or more telephone-lines, each ot' whichcontains devices at the subscribers7 stations for introducing theprimary of an induction-coil and a-batterytransmltter into theline-circuit, a central-ot'- ce switch to which said lines areconnected, and switch devices for connecting any two lines through abattery for oral communication, substantially as described.

CHARLES E. BUELL. Witnesses:

.GEORGE W. Cov, THOMAS TooMEY.

IOO

